ENGINE FUEL PART 3

To determine the float level in a float-type carburetor, a measurement is usually made from the top of the fuel in the float chamber to the. parting surface of the carburetor. top of the float. centerline of the main discharge nozzle.

A fuel strainer or filter must be located between the. boost pump and tank outlet. tank outlet and the fuel metering device. boost pump and engine-driven fuel pump.

Excessively rich or lean idle mixtures result in. too rapid completion of combustion. incomplete combustion. incomplete cylinder scavenging.

A rotary-vane pump is best described as a. positive-displacement pump. variable-displacement pump. boost pump.

What is the purpose of the flow divider in a turbine engine duplex fuel nozzle?. Allows an alternate flow of fuel if the primary flow clogs or is restricted. Creates the primary and secondary fuel supplies. Provides a flow path for bleed air which aids in the atomization of fuel.

What occurs when a back-suction type mixture control is placed in IDLE CUTOFF?. The fuel passages to the main and idle jets will be closed by a valve. The float chamber will be vented to a negative pressure area. The fuel passage to the idle jet will be closed by a valve.

Select the statement which is correct relating to a fuel level check of a float-type carburetor. Use 5 pounds fuel pressure for the test if the carburetor is to be used in a gravity fuel feed system. Block off the main and idle jets to prevent a continuous flow of fuel through the jets. Do not measure the level at the edge of the float chamber.

What are the principal advantages of the duplex fuel nozzle used in many turbine engines?. Restricts the amount of fuel flow to a level where more efficient and complete burning of the fuel is achieved. Provides better atomization and uniform flow pattern. Allows a wider range of fuels and filters to be used.

An aircraft carburetor is equipped with a mixture control in order to prevent the mixture from becoming too. lean at high altitudes. rich at high altitudes. rich at high speeds.

The use of less than normal throttle opening during starting will cause. a rich mixture. a lean mixture. backfire due to lean fuel/air ratio.

Boost pumps in a fuel system. operate during takeoff only. are primarily used for fuel transfer. provide a positive flow of fuel to the engine pump.

What will occur if the vapor vent float in a pressure carburetor loses its buoyancy?. The amount of fuel returning to the fuel tank from the carburetor will be increased. The engine will continue to run after the mixture control is placed in IDLE CUTOFF. A rich mixture will occur at all engine speeds.

One purpose of an air bleed in a float-type carburetor is to. increase fuel flow at altitude. meter air to adjust the mixture. decrease fuel density and destroy surface tension.

What is the final authority for the details of carburetor overhaul?. The local FAA safety inspector. The Type Certificate Data Sheets for the engine. The manufacturer's recommendations.

When a new carburetor is installed on an engine,. warm up the engine and adjust the float level. do not adjust the idle mixture setting; this was accomplished on the flow bench. and the engine is warmed up to normal temperatures, adjust the idle mixture, then the idle speed.

If the volume of air passing through a carburetor venturi is reduced, the pressure at the venturi throat will. decrease. be equal to the pressure at the venturi outlet. increase.

Fuel pressure produced by the engine-driven fuel pump is adjusted by the. bypass valve adjusting screw. relief valve adjusting screw. engine-driven fuel pump adjusting screw.

Which of the following best describes the function of an automatic mixture control (AMC)?. It compensates for change in the air density due to temperature and altitude. It compensates for the air pressure above the fuel in the float chamber. It compensates for the air pressure in the venturi of a float-type carburetor.

Where is the engine fuel shutoff valve usually located?. Aft of the firewall. Adjacent to the fuel pump. Downstream of the engine-driven fuel pump.

What factor is not used in the operation of an aircraft gas turbine engine fuel control unit?. Compressor inlet air temperature. Mixture control position. Power lever position.

What effect does high atmospheric humidity have on the operation of a jet engine?. Decreases engine pressure ratio. Decreases compressor and turbine RPM. Has little or no effect.

What precaution should be taken when putting thread lubricant on a tapered pipe plug in a carburetor float bowl?. Put the thread lubricant only on the first thread. Do not use thread lubricant on any carburetor fitting. Engage the first thread of the plug, then put a small amount of lubricant on the second thread and screw the plug in.

Which of the following is least likely to occur during operation of an engine equipped with a direct cylinder fuel injection system?. Afterfiring. Kickback during start. Backfiring.

Why must a float-type carburetor supply a rich mixture during idle?. Engine operation at idle results in higher than normal volumetric efficiency. Because at idling speeds the engine may not have enough airflow around the cylinders to provide proper cooling. Because of reduced mechanical efficiency during idle.

A major difference between the Teledyne-Continental and RSA (Precision Airmotive or Bendix) continuous flow fuel injection systems in fuel metering is that the. RSA system uses air pressure only as a metering force. Continental system utilizes airflow as a metering force. Continental system uses fuel pressure only as a metering force.

When checking the idle mixture on a carburetor, the engine should be idling normally, then pull the mixture control toward the IDLE CUTOFF position. A correct idling mixture will be indicated by. an immediate decrease in RPM. a decrease of 20 to 30 RPM before quitting. an increase of 10 to 50 RPM before decreasing.

The desired engine idle speed and mixture setting. is adjusted with engine warmed up and operating. should give minimum RPM with maximum manifold pressure. is usually adjusted in the following sequence; speed first, then mixture.

(Refer to Figure 6.) Which curve most nearly represents an aircraft engine's air-fuel ratio throughout its operating range?. 1. 3. 2.

A carburetor is prevented from leaning out during quick acceleration by the. power enrichment system. mixture control system. accelerating system.

If an aircraft engine is equipped with a carburetor that is not compensated for altitude and temperature variations, the air-fuel mixture will become. leaner as either the altitude or temperature increases. richer as the altitude increases and leaner as the temperature increases. richer as either the altitude or temperature increases.

During the operation of an aircraft engine, the pressure drop in the carburetor venturi depends primarily upon the. air temperature. barometric pressure. air velocity.

Generally, the practice when trimming an engine is to. turn all accessory bleed air off. turn all accessory bleed air on. make adjustments (as necessary) for all engines on the same aircraft with accessory bleed air settings the same -- either on or off.

An electronic engine control (EEC) is a system that receives engine operating information and. adjusts a standard hydromechanical fuel control unit to obtain the most effective engine operation. develops the commands to various actuators to control engine parameters. controls engine operation according to ambient temperature, pressure, and humidity.

On a carburetor without an automatic mixture control as the aircraft ascends to altitude, the mixture will. be enriched. be leaned. not be affected.

What corrective action should be taken when a carburetor is found to be leaking fuel from the discharge nozzle?. Replace the needle valve and seat. Adjust the mixture control. Adjust throttle linkage.